Chap 18

1

• Chap 18
• Review the thermochemistry in Chapter 6
• What does it mean to say a reaction is
  spontaneous or non-spontaneous? Can you
  recognize certain processes as one or the other?
• How is spontaneity of a reaction affected by
  enthalpy, entropy, and temperature? Under what
  conditions of temperature will a reaction be
  spontaneous or nonspontaneous?
• What is entropy? What does it (really) measure?
• What are the units of entropy?
• Can you compare two systems and say which one
  has more or less entropy (compounds vs. elements,
  related compounds, solutions vs. pure substances,
  hot vs. cold, solid vs. liquid, etc.)? Can you
  recognize when a process is likely to be entropy
  increasing or decreasing (why are gases
  noteworthy here)?

2

• Chap 18
• Can you calculate the DS0 of a reaction from the
  standard entropies of reactants and products?
• What are the four Laws of Thermodynamics, both
  in English and in mathematics?
• Gibbs free energy, DG
• How does this number predict whether a reaction
  is spontaneous or nonspontaneous, or whether a
  reaction is in equilibrium?
• Can you calculate the standard free energy
  change DG0 of a reaction from the standard free
  energies of the reactants and products?
• Can you calculate DG from DH, DS, and
  temperature T of reaction? Can you tell from DH
  and DS under what conditions the process becomes
  (non)spontaneous? Can you predict the
  approximate temperature at which the reaction
  crosses from spontaneous to nonspontaneous?

3

• Chap 18 (cont)
• Can you calculate the equilibrium constant Keq
  of a reaction at a given temperature if you know
  its standard free energy DG0, and vice versa?
• Can you calculate the free energy change DG of a
  reaction if you know its standard free energy DG0
  and can account for current nonstandard
  conditions (Q and T)?

4

• Chap 19
• Review the redox reactions material in Section
  4.4
• Know the oxidation number rules
• What are half-reactions? Can you identify the
  oxidation h-r and the reduction h-r in a chem eq?
• Can you correctly balance a redox reaction?
• Electrochemical cells
• What is a cell? What are its various parts?
• What chemistry is occuring at the anode/cathode
  of a cell?
• Can you write the cell diagram?
• What is the emf of a cell? What units is it
  measured in?
• What are standard reduction potentials (s.r.p.)?
• Can you identify which materials in a cell will
  be acting as the anode or cathode from the
  s.r.p.?
• Can you use s.r.p. to determine which materials
  are more powerfully oxidizing/reducing?